My home-made genturi runs right outside my dinette window. It has never given me any problem. The pipe at that level stays cool to the touch.
I suggest you try yours and confirm that it is cool to touch when running. Even if it is warm it won't cause a problem unless it is quite hot. Mine is about 4" from the window but even if it was closer it is cool so it wouldn't cause a problem.
Class C, 2004/5 Four Winds Dutchman Express 28A, Chevy chassis
2010 Subaru Impreza Sedan
Camped in 45 states, 7 Provinces and 1 Territory